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PubMed1988

Effects of ascorbic acid and thiocyanate on nitrosation of proline in the dog stomach.

To elucidate the factors governing the formation of N-nitrosamines in the stomach, the formation of N-nitrosoproline (NPro) was studied under controlled conditions, using a dog equipped with a Thomas cannula. Solutions containing nitrite, proline and in some cases ascorbic acid and/or SCN-, were infused into the stomach and samples taken to determine gastric [nitrite], [NPro], [ASC], [SCN-] and pH as functions of time. (Brackets indicate molar concentrations; ascorbic acid and ascorbate ion are denoted together by ASC.) Previous work showed that the rapid decline of [nitrite] in the stomach was due primarily to absorption. Additional experiments here in which ASC, proline or NPro were infused together with a non-absorbable marker, in the absence of nitrite, demonstrated that there was negligible absorption or secretion of these substances in the stomach. Thus, changes in [ASC] and [NPro] with time could be interpreted quantitatively in terms of rates of chemical reaction and dilution of the stomach contents. A mathematical model, based on mass balance equations for the various chemical species and chemical kinetic data obtained previously from in vitro studies, was developed for this purpose. The ability of ASC to inhibit nitrosation (by reaction with nitrite) was shown to be highly dependent on initial [ASC] and on the rate of entry of O2 into the stomach from blood. The rate of NPro formation in the absence of ASC and SCN-, the inhibitory effects on nitrosation of ASC and the catalytic effects of SCN-, were all accurately predicted by the mathematical model. This suggests that similar models may prove useful in estimating rates of intragastric N-nitrosation reactions in humans, under various assumed conditions.

Animals↗

PubMed1980

Meiosis in Neurospora crassa. II. Genetic and cytological characterization of three meiotic mutants.

Three recessive meiotic mutants, asc(DL95), asc(DL243) and asc(DL879), were detected by the abortion of many of their ascospores and were analyzed using both cytological and genetic methods. Even though asc(DL95), asc (DL243) and the previously studied meiotic mutant, mei-1 (Smith 1975; Lu and Galeazzi (1978), complement one another in crosses, they apparently do not recombine (DeLange and Griffiths (1980). Thus, they may represent alleles of the same gene or comprise a gene cluster. Ascospore abortion in these mutants is caused by abnormal disjunction of meiotic chromosomes. In crosses homozygous for asc(DL95), asc(DL879) or mei-1, both pairing of homologs and meiotic recombination frequencies are reduced. In each case, this primary defect is followed by the formation of univalents at metaphase I and their irregular segregation. The mutant asc(DL243) has a defect in ascus formation, and later in disjunction during the second meiotic and post-meiotic divisions. The first-acting defect before or during karyogamy results in the abortion of most cells. Some cells manage to proceed past this block. During the second meiotic division, most chromosomes of the few resulting asci are attached to only one of the two spindle-pole bodies. Disjunction at the post-meiotic division is also highly irregular. This mutant appears to be defective in the attachment of one spindle-pole body to a set of chromosomes. The defect may involve either a centromere-associated product or a spindle-pole body.

Genes, Recessive↗

PubMed1998

A tacrolimus-related immunosuppressant with reduced toxicity.

BACKGROUND: Tacrolimus (FK506) has potent immunosuppressive properties reflecting its ability to block the transcription of lymphokine genes in activated T cells through formation of a complex with FK506 binding protein-12, which inhibits the phosphatase activity of calcineurin. The clinical usefulness of tacrolimus is limited, however, by severe adverse effects, including neurotoxicity and nephrotoxicity. Although this toxicity, like immunosuppression, appears mechanistically related to the calcineurin inhibitory action of the drug, a large chemistry effort has been devoted to search for tacrolimus analogs with reduced toxicity but preserved immunosuppressive activity that might have enhanced therapeutic utility. METHODS: Here, we report on the identification of such an analog, which was synthetically derived from ascomycin (ASC), the C21 ethyl analog of tacrolimus, by introducing an indole group at the C32 position. The profile of biological activity of indolyl-ASC was characterized in rodent models of immunosuppression and toxicity. RESULTS: Indolyl-ASC was found to exhibit an immunosuppressive potency equivalent to that of tacrolimus in T-cell activation in vitro and in murine transplant models, even though indolyl-ASC bound about 10 times less to intracellular FK506 binding protein-12 than tacrolimus or ASC. Further evaluation of indolyl-ASC revealed that it is threefold less potent than tacrolimus in inducing hypothermia, a response that may reflect neurotoxicity, and in causing gastrointestinal transit alterations in mice. Moreover, indolyl-ASC was at least twofold less nephrotoxic than tacrolimus upon 3-week oral treatment in rats. CONCLUSIONS: Altogether, these data indicate a modest but definite improvement in the therapeutic index for indolyl-ASC compared with tacrolimus in rodent models.

Animals↗

PubMed2005

Cytopathology update on atypical squamous cells.

The most common abnormality reported by cervical cytology (Pap tests) is atypical squamous cells (ASC). The two subcategories are ASC of undetermined significance (ASCUS) and ASC, cannot exclude high-grade squamous intraepithelial lesion (ASC-H). ASCUS show morphology suspicious for a low-grade lesion, while ASC-H cells are suspicious for a high-grade process. ASCUS account for most ASC reports, and the 2002 median ASCUS reporting rates were 3.1% for conventional smears and 4.1% for liquid-based preparations. Reporting rates for squamous intraepithelial lesions and cancer (SIL+) were also higher for liquid-based preparations, and thus the median ASC/SIL+ ratio was lower for liquid-based preparations (1.27) than for conventional smears (1.44). Interobserver reproducibility for ASC is generally considered lower than for other squamous epithelial abnormalities. Women with ASCUS may be managed by human papillomavirus DNA testing, repeated cytology, or colposcopy, while women with ASC-H should generally proceed to colposcopy.

American Cancer Society↗

PubMed2005

Increasing tolerance to ozone by elevating foliar ascorbic acid confers greater protection against ozone than increasing avoidance.

Ascorbic acid (Asc) is the most abundant antioxidant in plants and serves as a major contributor to the cell redox state. Exposure to environmental ozone can cause significant damage to plants by imposing conditions of oxidative stress. We examined whether increasing the level of Asc through enhanced Asc recycling would limit the deleterious effects of environmental oxidative stress. Plants overexpressing dehydroascorbate reductase (DHAR), which results in an increase in the endogenous level of Asc, were exposed to acute or chronic levels of ozone. DHAR-overexpressing plants had a lower oxidative load, a lower level of oxidative-related enzyme activities, a higher level of chlorophyll, and a higher level of photosynthetic activity 24 h following an acute exposure (2 h) to 200 ppb ozone than control plants, despite exhibiting a larger stomatal area. Reducing the size of the Asc pool size through suppression of DHAR expression had the opposite effect. Following a chronic exposure (30 d) to 100 ppb ozone, plants with a larger Asc pool size maintained a larger stomatal area and a higher oxidative load, but retained a higher level of photosynthetic activity than control plants, whereas plants suppressed for DHAR had a substantially reduced stomatal area, but also a substantially lower level of photosynthetic activity. Together, these data indicate that, despite a reduced ability to respond to ozone through stomatal closure, increasing the level of Asc through enhanced Asc recycling provided greater protection against oxidative damage than reducing stomatal area.

Ascorbic Acid↗

PubMed2003

Cyclo(-Cha-Oxz-D-Val-Thz-Ile-Oxz-D-Val-Thz-) N,N-dimethylacetamide dihydrate: a square form of cyclohexylalanine-incorporated ascidiacyclamide having the strongest cytotoxicity.

The title compound, 1-cyclohexylmethyl-1-de(1-methylpropyl)ascidiacyclamide N,N-dimethylacetamide dihydrate, C(39)H(56)N(8)O(6)S(2) x C(4)H(9)NO x 2H(2)O, a cyclohexylalanine-incorporated ascidiacyclamide analogue ([Cha]ASC), shows a square form similar to natural ASC. On the other hand, CD (circular dichroism) spectra showed [Cha]ASC to have a folded structure in solution, making it the second known analogue to show a discrepancy between its crystal and solution structures. Moreover, the cytotoxicity of [Cha]ASC (ED(50) = 5.6 micro g ml(-1)) was approximately two times stronger than that of natural ASC or a related phenylalanine-incorporated analogue, viz. cyclo(-Phe-Oxz-D-Val-Thz-Ile-Oxz-D-Val-Thz-) ([Phe]ASC), and was confirmed to be associated with the square form. However, [Phe]ASC was previously shown to be folded in the crystal structure, which suggests that the difference between the aromatic and aliphatic rings affects the molecular folding of the ASC molecule.

Amino Acids↗

PubMed2004

Relationship of airway symptoms from chemicals to capsaicin cough sensitivity in atopic subjects.

BACKGROUND: It is well known that some patients with allergy complain of airway symptoms from chemicals (ASCs) and strong odours. However, the importance of such information for the treatment of allergic disease is not known. Such symptoms in non-allergic patients have previously been shown to be related to increased sensory nerve reactivity, which is expressed as increased cough sensitivity to inhaled capsaicin. OBJECTIVE: The aim of this study was to examine ASC in atopic patients and relate it to cough reaction to capsaicin inhalation. MATERIALS AND METHODS: Fifty-seven consecutively chosen, skin prick-positive patients with symptoms of the upper and/or lower airways completed a questionnaire concerning ASC. The patients were then divided into two groups, those with and those without such symptoms. Both groups were provoked with inhaled capsaicin in three increments and compared with 73 healthy control subjects. RESULTS: Out of 57 atopic patients, 34 reported ASC agents and 23 did not. The patients with ASC were older (P<0.01) and coughed significantly more on capsaicin provocation (P<0.001), but did not differ from them with respect to the allergic disease or its treatment or to smoking habits. Patients with atopy but without ASC did not differ from healthy controls with regard to sensitivity to capsaicin inhalation. The scored degree of ASC was directly related to the number of coughs during the capsaicin provocation. CONCLUSION: ASC in atopic patients are related to increased airway sensory nerve reactivity. There is still no explanation for this in certain patients with atopy, but age may be a confounding factor.

Adolescent↗

PubMed2005

Components of apoplastic ascorbate use in Betula pendula leaves exposed to CO2 and O3 enrichment.

Here, the aim was to estimate loads imposed on the apoplastic ascorbate (ASC) pool by enzymatic and nonenzymatic reactions in Betula pendula exposed to doubled CO2 and O3 concentrations in open-top chambers. Leaf apoplastic extracts were analysed for peroxidase and oxidase activities in vitro, using different substrates. Partial loads in vivo were deduced using measured kinetic constants and substituted-enzyme catalysis approaches. Ascorbate use in O3 scavenging was calculated using measured stomatal conductances and ASC concentrations. Under elevated O3, stomatal conductance and O3 uptake were higher. O3 fluxes to the plasmalemma were levelled off by higher apoplastic ASC concentrations. The effect of CO2 enrichment on ASC concentrations under elevated O3 was minor. Under ambient O3, the ascending hierarchy of ASC users was: peroxidases, O3 scavenging, oxidases, coniferyl alcohol re-reduction. Under elevated O3, ASC use in O3 scavenging was higher than by oxidases. The redox state of ASC was not depressed by O3; there was no leaf injury. The cell wall/plasmalemma/cytosol system in birch had sufficient capacity to maintain ASC redox status in the apoplast, without necessity to restrict O3 uptake by stomatal closure.

Ascorbic Acid↗

PubMed2006

Effects of acidified sodium chlorite, cetylpyridinium chloride and hot water on populations of Listeria monocytogenes and Staphylococcus aureus on beef.

AIMS: The present study was designed to determine the individual and combined effects of acidified sodium chlorite (ASC, 0.1%, 24 +/- 1 degrees C), cetylpyridinium chloride (CPC, 0.5%, 24 +/- 1 degrees C) and hot water (HW, 93 +/- 1 degrees C) treatments on the survival of Listeria monocytogenes and Staphylococcus aureus. METHODS AND RESULTS: Beef samples inoculated with L. monocytogenes and S. aureus were treated with nine different applications singly or in combination. Treatment groups comprised (i) untreated control; (ii) sterile tap water; (iii) 0.1% ASC; (iv) 0.5% CPC; (v) HW; (vi) HW followed by 0.1% ASC; (vii) HW followed by 0.5% CPC; (viii) 0.1% ASC followed by HW; (ix) 0.5% CPC followed by HW. Compared with the untreated control group, the reductions in L. monocytogenes populations were 1.14-2.31 log CFU g(-1), while the reductions in S. aureus populations were 0.83-2.74 log CFU g(-1) on day 0. CONCLUSION: The reduction effect that occurred after combined treatment with ASC followed by HW, HW followed by ASC, CPC followed by HW and HW followed by CPC was found to be significantly greater (P < 0.05) than after treatment with ASC and CPC alone on days 0, 2 and 4 of storage. SIGNIFICANCE AND IMPACT OF THE STUDY: ASC, CPC and HW treatments can be used to reduce L. monocytogenes and S. aureus, which would provide an additional measure of safety on the production line.

Animals↗

PubMed1997

Standardization of measurement of immunoglobulin-secreting cells in human peripheral circulation.

A sensitive, and at times the most sensitive, measurement of human vaccine immunogenicity is enumeration of antibody-secreting cells (ASC) in peripheral blood. However, this assay, which is inherently capable of measurement of the absolute number of antigen-specific ASC, is not standardized. Thus, quantitative comparison of results between laboratories is not currently possible. To address this issue, isotype-specific ASC were enumerated from paired fresh and cryopreserved mononuclear cell (MNC) preparations from healthy adult volunteers resident in either the United States (US group) or Egypt (EG group). Analysis of fresh cells from US volunteers revealed mean numbers of ASC per 10(6) MNC of 617, 7,738, and 868 for immunoglobulin M (IgM), IgG, and IgA, respectively, whereas EG volunteers had 2,086, 7,580, and 1,677 ASC/10(6) MNC for the respective isotypes. Cryopreservation resulted in a slight reduction in group mean IgM, IgG, and IgA ASC (maximum reduction in group mean, 14%), but in no instance were results obtained with cryopreserved cells significantly lower than those obtained with fresh cells. To determine if cryopreservation affected the number of bacterial antigen-specific ASC detected, cells from a group of US adult volunteers who received a single oral dose of a mutated Escherichia coli heat-labile enterotoxin (LT(R192G)) were tested. There was no significant difference (P > 0.05) in the number of antigen-specific IgA or IgG ASC detected between fresh and cryopreserved MNC. The results support the views that ASC assays can be standardized to yield quantitative results and that the methodology can be changed to make the test more practical.

Adult↗

PubMed1999

Effects of maternal antibodies on protection and development of antibody responses to human rotavirus in gnotobiotic pigs.

Although maternal antibodies can protect against infectious disease in infancy, they can also suppress active immune responses. The effects of circulating maternal antibodies, with and without colostrum and milk antibodies, on passive protection and active immunity to human rotavirus (HRV) were examined in gnotobiotic pigs. Pigs received intraperitoneal injections of high-titer serum (immune pigs [groups 1 and 2]) from immunized sows, low-titer serum from naturally infected sows (control pigs [groups 3 and 4]), or no serum (group 5). Immune or control colostrum and milk were added to the diet of groups 2 and 4, respectively. After inoculation (3 to 5 days of age) and challenge (postinoculation day [PID] 21) with virulent HRV, the effects of maternal antibodies on protection (from diarrhea and virus shedding), and on active antibody responses (measured by quantitation of antibody-secreting cells [ASC] in intestinal and systemic lymphoid tissues by ELISPOT) were evaluated. Groups 1 and 2 had significantly less diarrhea and virus shedding after inoculation but higher rates of diarrhea and virus shedding after challenge than did groups 3 and 5. Group 1 and 2 pigs had significantly fewer immunoglobulin A (IgA) ASC in intestinal tissues at PID 21 and at postchallenge day (PCD) 7 compared to group 5. Significantly fewer IgG ASC were present in the intestines of group 2 pigs at PID 21 and PCD 7 compared to group 5. There was a trend towards fewer ASC in intestinal tissues of group 2 than group 1, from PID 21 on, with significantly fewer IgA ASC at PCD 7. IgG ASC in the duodenum and mesenteric lymph nodes of group 3 and 4 pigs were significantly fewer than in group 5 at PCD 7. These decreases in ASC emphasize the role of passive antibodies in impairing induction of ASC rather than in merely suppressing the function of differentiated B cells. To be successful, vaccines intended for populations with high titers of maternal antibodies (infants in developing countries) may require higher titers of virus, multiple doses, or improved delivery systems, such as the use of microencapsulation or immune stimulating complexes, to overcome the suppressive effects of maternal antibodies.

Animals↗

PubMed1997

Ascorbate deficiency and oxidative stress in the alveolar type II cell.

The objective of this study was to determine the impact of limited ascorbate (Asc) availability on type II cell sensitivity to oxidant stress. Guinea pigs were fed diets with or without Asc for 18 days, and type II cells were isolated. Although lung Asc was decreased by 90% in deficient animals (scorbutic), type II cell Asc was decreased by 50%. Upon treatment with 250 microM H2O2, the necrotic injury was twofold greater in scorbutic cells compared with control cells. With 100 microM H2O2 treatment, apoptotic injury was twofold greater in scorbutic cells compared with control cells. Although there was less necrotic injury in cells exposed to 95% O2, the scorbutic cells were more sensitive than control cells. Asc pretreatment protected against necrosis and apoptosis. The Asc analog isoascorbate provided partial protection and suggested that part of the protection was not chemical detoxification but was Asc specific. We conclude that limited Asc availability resulted in a functional type II cell but a cell more sensitive to oxidant-induced injury.

Animals↗

PubMed2003

Hepatitis B virus DNA in anti-HBe-positive asymptomatic carriers.

OBJECTIVES: We examined the level of hepatitis B virus (HBV) DNA and the mutations in the precore, core and polymerase regions of HBV in sera from anti-HBe-positive asymptomatic carriers (ASC). METHODS: The amount of HBV DNA was determined semiquantitatively by mutation site-specific assay in sera from 19 anti-HBe-positive ASC and 31 HBeAg-positive patients with chronic liver disease (CLD). The mutations in the precore, core and polymerase (terminal protein) regions, spanning 1,037 nucleotides, of HBV in sera from three cases each of anti-HBe-positive ASC, HBeAg-positive ASC and HBeAg-positive CLD were examined by directly sequencing the amplified HBV DNA. RESULTS: The level of HBV viremia in anti-HBe-positive ASC was significantly lower than that in HBeAg-positive CLD patients (p < 0.01). By sequence analysis, there were a few missense mutations detected in HBeAg-positive ASC and HBeAg-positive CLD patients. In contrast, many mutations, especially in the central or N-terminal half of the core region and N-terminal part of the polymerase region, were detected in anti-HBe-positive ASC. CONCLUSION: Mutations not only in the precore/core region, but also in the polymerase region of HBV might cause damage to some important functions for efficient replication of HBV and be involved in the reduced amount of HBV in anti-HBe-positive ASC.

Adult↗

PubMed2004

Adenosquamous carcinoma of the esophagus. Clinicopathologic study of 18 cases.

OBJECTIVES: Adenosquamous carcinoma (ASC) of the esophagus is an uncommon form of esophageal cancer. Despite isolated case reports on this tumor type, no large clinicopathologic series appears to have been studied at a single institution. METHODS: At our institution, 20 cases of ASC were diagnosed pathologically between 1970 and 2001 (20/2,056 total esophageal cancers; 1.0%). Excluding 2 patients who received preoperative radiation therapy, 18 were selected for review of their clinicopathologic features, including survival time, in comparison with those of patients with conventional squamous cell carcinomas (SCCs; n = 850) and adenocarcinomas (ACs; n = 40) of the esophagus. RESULTS: The location and macroscopic type of the ASCs were similar to those of the SCCs. ASC tumors were significantly smaller than SCC (p = 0.004) and AC (p = 0.012) tumors, and the depth of invasion of ASCs was significantly less than that of SCCs (p = 0.028). Lymphatic permeation and blood vessel invasion were seen in 14 (77.8%) and 7 (38.9%) of the 18 patients with ASCs, respectively, and intraepithelial carcinoma contiguous to the main lesion was evident in 10 cases (56.6%). The cumulative postoperative survival rates of patients with ASC at 3, 5 and 10 years were 71.5, 63.6 and 47.7%, respectively, the outcome being significantly better than for patients with either SCC (p = 0.027) or AC (p = 0.013). CONCLUSION: In the esophagus, ASCs have better prognosis than conventional SCCs or ACs, probably due to their smaller size and lower stage.

Aged↗

PubMedDate not supplied

High-risk HPV DNA detection rate in patients with atypical squamous cells and its relationship to the atypical squamous cell: squamous intraepithelial lesion ratio.

OBJECTIVE: To determine if there is any relationship between the atypical squamous cell (ASC):squamous intraepithelial lesion (SIL) ratio and high-risk HPV DNA detection rate. STUDY DESIGN: Data on the frequency of various cytologic diagnoses for each pathologist were retrieved from 2002 to 2003. ASC:SIL ratio for each pathologist was calculated. In addition, data related to high-risk HPV detection rate was obtained during the study period. HPV DNA testing was performed using HC II (Digene, Gaithersburg, Maryland U.S.A). Cases with insufficient quantity were excluded. RESULTS: Five pathologists, with experience ranging from 2 to 15 years, reviewed Pap tests during the study period. For the entire laboratory, the ASC:SIL ratio was 2.0, and the high-risk HPV DNA detection rate in ASC specimens was 31%. For individual pathologists, ASC:SIL ratio ranged from 1.2 to 4.0 and high-risk HPV DNA detection rate from 31% to 38%. No significant correlation was noted between the ASC:SIL ratio and high-risk HP DNA detection rate. CONCLUSION: Our ASC:SIL ratios (except for 1 pathologist) and high-risk HPV DNA detection rates were within an acceptable range. We did not observe any association between ASC:SIL ratio and high-risk HPV detection rate.

Cervix Uteri↗

PubMed2003

Stability of ascending aortic dilatation following aortic valve replacement.

BACKGROUND: Replacement of the ascending aorta (Asc Ao) at the time of aortic valve replacement (AVR) is controversial because the risk of progressive dilatation following valve replacement is uncertain. Our aim was to determine the natural history of ascending aortic dilatation following AVR. METHODS AND RESULTS: We studied 185 patients undergoing AVR at our institution between 1992 and 1999. Clinical and echocardiographic data were obtained by merging our institutional echocardiographic database with the DHMC component of the Northern New England Cardiovascular Disease Study Group database. Baseline Asc Ao measurements obtained from intraoperative transesophageal echocardiograms or early (<8 weeks) postoperative transthoracic echocardiograms were compared with late follow-up measurements (mean follow-up 30.0+/-23.4 months). During follow-up, there was no increase in the mean Asc Ao diameter (3.6+/-0.6 cm versus 3.6+/-0.6 cm, p=NS). Progressive aortic dilatation, defined as an increase in diameter >0.3 cm, occurred in 27/185 patients (15%). Baseline Asc Ao dilatation (>or=3.5 cm) was present in 107/185 patients (58%). In this subset of patients, there was no increase in mean Asc Ao diameter (4.0+/-0.4 versus 3.9+/-0.6 cm, p=NS) and progressive aortic dilatation occurred in only 10 patients (9.3%). No patients with baseline aortic dilatation (range, 3.5 to 5.3 cm) dilated beyond 5.5 cm on follow-up (range, 2.4 to 5.5 cm). There were no clinical or valvular characteristics that predicted progressive Asc Ao dilatation. CONCLUSIONS: An increase in Asc Ao dilatation occurs infrequently following AVR and therefore, argues against routine Asc Ao replacement at the time of AVR.

Aged↗

PubMed1992

Dysfunction of nonadrenergic noncholinergic inhibitory system after antigen inhalation in actively sensitized cat airways.

We have investigated whether proteases released during antigen inhalation cause dysfunction of the nonadrenergic noncholinergic inhibitory nervous system (NANCIS). Frequency-response (F-R) studies of NANCIS were performed before and after Ascaris antigen (ASC) inhalation using actively sensitized cats. NANC dilatatory effects were obtained by stimulating bilateral cervical vagi under cholinergic and beta-adrenergic blockade and serotonin-induced bronchoconstriction, and assessed by maximal percent relaxation (rmax) and the frequency causing 50% of maximal relaxation (EF50). ASC inhalation caused a transient increase in pulmonary resistance in all animals. One hour after ASC inhalation, pulmonary resistance returned to the baseline value, but ASC inhalation significantly attenuated NANC inhibitory activities: rmax decreased from 82.2 +/- 4.7 (mean +/- SE) to 64.3 +/- 11.2% (p less than 0.05), and the geometric mean of EF50 increased from 1.7 to 4.3 Hz (p less than 0.05). Dilatatory effects of infused VIP, a possible neurotransmitter of NANCIS, was also attenuated after ASC inhalation. Pretreatment with leupeptin (3 mg/kg) abolished ASC-induced impairment of NANC inhibitory activities. By contrast, dilatatory effects of adrenergic nerve stimulation were not affected by ASC inhalation. These results suggest that NANC inhibitory activities can be impaired after ASC inhalation, and that this impairment of NANCIS may be due to effects of proteases released during allergic reaction.

Administration, Inhalation↗

PubMed1995

Interaction of lactoferrin with ascorbate and the relationship with bleomycin-dependent DNA damage.

The interaction between bovine lactoferrin (bLf) and ascorbate (Asc) was investigated through malondialdehyde (MAD) formation in a solution containing DNA, bleomycin (BLM), and Fe2+ or Asc. The inhibition by bLf on MDA formation in the presence of Asc was not changed even by adding carbonate or oxalate ions to the solution. The percentage inhibition by the hydrolysates of bLf treated with pepsin, trypsin, and both enzymes on MDA formation was almost the same as that by the untreated bLf in the presence of Asc. The inhibition of MDA formation also occurred with the filtrate obtained from a solution containing bLf and Asc, but not with that from a solution of bovine serum albumin and Asc. The interaction of bLf and Asc was observed by gel filtration in a Sephadex G75 column. The binding amount of Asc was estimated to be 87 mol per mole of bLf.

Amino Acids↗